Different types of vaccines

  • BCG vaccine. A bacterium (bacillus) named after Calmette and Guérin. This is a live, freeze-dried vaccine prepared from an attenuated strain of bovine (cattle) TB. BCG is required in South Africa at birth. If no scar is visible at three months, then the vaccine is repeated. South Africa still has a high rate of TB infection in spite of this vaccination, but it seems to protect children against TB meningitis and miliary (widely disseminated) TB, both more common among the developing part of our population, and both potentially fatal.
  • DPT and DT vaccine. These are inactivated vaccines, producing immunity to diphtheria, tetanus and pertussis, or just diphtheria and tetanus in the DT vaccine. The tri-valent vaccine is administered by intra-muscular injection to infants at six, 10 and 14 weeks and at 18 months in South Africa. Diptheria is caused by the bacterium Corynbacterium diptheriae.It is a severe infection of the throat in which a membrane forms which can block the airway and cause suffocation. It used to occur in epidemics associated with a high mortality. It is largely unknown in the developed world. Tetanus, also known as lockjaw, is a serious illness caused by the bacterium Clostridium tetani. This organism is found in the gut of animals and the soil and may gain entry into the body through open wounds (e.g. dog bites). It is present worldwide and can affect any age. It is potentially fatal, particularly in young children. Pertussis or whooping cough, although a mild illness in older children, can cause severe infection of the respiratory tract in children under one year and is particularly dangerous to those under one month.
  • The Hib vaccine. This vaccine protects against serious disease caused by a bacterium called Haemophilus influenzae type B, particularly meningitis. The vaccine contains only the coat proteins of the bacterium, and is safe and effective.
  • Polio vaccine. There are two vaccines that protect against poliomyelitis, namely the inactivated poliovirus vaccine (IPV), known as the Salk vaccine, which is given by injection and the oral, live attenuated vaccine (OPV) which is administered orally. This is also called the Sabin vaccine. In South Africa the oral polio vaccine (OPV) is used. Doses are given to infants at birth, six, 10 and 14 weeks of age and again at 18 months and six years. Polio is a potentially devastating disease, still endemic in Africa. At its worst it results in paralysis, again an illness your grandparents may remember. Even those in their 40s may have had friends at school who used calipers on their legs as a result of childhood polio infection leaving them with weak, damaged muscles.
  • Hepatitis B vaccine. Hepatitis B is endemic in Africa, which is why routine immunisation of children has been introduced fairly recently (in 1995). It can cause a serious disease of the liver, for which there is no cure, and may lead to death or chronic liver problems which will persist into adult life. The vaccine contains only the coat protein (surface antigen) which covers the surface of the virus. It is prepared from the plasma of human carriers, or produced by recombinant DNA technology in yeasts. Both types have been shown to be equally safe and effective.
  • Measles vaccine:. Measles causes an acute febrile illness with a rash which can be life threatening in young children. The vaccine consists of a weakened strain of the measles virus. It is given to children over the age of nine months.

Reviewed by Dr Diana Hardie, Clinical Virologist employed jointly by the University of Cape Town and the National Health Laboratory Service (NHLS)
Reviewed May 2007

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